It improves the coverage of the ActivityPub standard and the interoperability between Mastodon. This feature also sometimes brings additional information about the account.
Do we really want users to control their own actor_type? What happens if a user sets their actor_type to Application? We already have one assumption that if you're not Person or Service that we shouldn't try to update follower/following counts for that user.
I'm thinking a better proposal would be if a user sets their account to bot we then report actor_type as Service, but not let them change their actor_type to any arbitrary value.
How do we want to control this from the Admin API side? Should we allow AdminFE to set arbitrary actor_type and also enable/disable bot flag on accounts? Or should actor_type and bot flag always be linked?
I think for now we should just restrict to Service and Person, the other ones seem like footguns at the moment, there's no real use for them but it might break things in the future